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No answer but same goal from me in a quite different context : I work
with aerial photos under a stereoscope, and happen to make my own
orthophotographs. I need to compare photo-interpretations with other <i>georectified
</i>data.<br>
So I often think it would be perfect if I could "un-project" data with
the reverse transformation used to orthorectify, then superimpose the
result on aerial photos, and finally analyse it under the stereoscope.<br>
<a href="http://perso.orange.fr/bain.vincent/sample.jpg">Here</a> is an
example ("hand made" so very rough).<br>
<br>
Vincent.<br>
<br>
Dwight Needels a écrit :
<blockquote cite="mid:C329DE57.20ECC%25needels@translucida.com"
type="cite">
<title>Reverse i.rectify</title>
<font face="Verdana"><span style="font-size: 12px;">I have a historic
map that I georeferenced using i.rectify. To help me compare features
to modern maps, I have overlaid a 1’ lon/lat grid.<br>
<br>
I would like to display the undistorted original XY map with the
lon/lat grid back-projected on top to show the geometric distortion. In
other words, I want the originally straight lines of the grid displayed
as curves based on the reverse of the i.rectify transformation.<br>
<br>
Is there any way to extract the transform parameters and use them to
reverse the i.rectify transformation? Are there other ways to
accomplish something similar?<br>
<br>
Thanks,<br>
<br>
-Dwight</span></font>
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